Reconnaissance and surveillance of hazardous areas or sites of interest are of value to civilian and government agencies alike. While by no means a complete list, hostage and survivor rescue missions, illicit drug raids, reconnaissance, and response to chemical or toxic waste spills are some of the operations that may benefit from a reconnaissance or surveillance component.
Although various systems may satisfactorily provide this capability, one promising solution is provided by the use of small, remotely-operated (or autonomous/semi-autonomous), ground traversing robotic vehicles. Although such miniature robots may be advantageous for their ease of transport to a deployment location and their ability during operation to maneuver in tight spaces, they are generally limited in the terrain and obstacles over which they can navigate when compared to their larger counterparts.
Improving the mobility of small robots is limited by a variety of factors. For instance, the small size of the platform imposes energy constraints by limiting the size of the robot's on-board energy source. Further for example, terrain over which the robot is intended to traverse may pose challenges (e.g., excessive undulations, obstacles, etc.) that are of little consequence to larger units.
Various solutions have been proposed to enable small robots to walk or roll over rough terrain, see, e.g., U.S. Pat. Nos. 6,548,982 to Papanikolopoulos et al., and U.S. Pat. No. 6,860,346 to Burt et al. While these solutions effectively permit travel of smaller robotic vehicles over elevational variations in terrain, they may not enable a robot to traverse treacherous terrain or obstacles of substantial height relative to the robot's size.
One solution proposed is to incorporate a fixed-wing flight mode into an otherwise ground-traversing robot. Such a robot would be able to traverse unforgiving terrain and obstacles by flying over them. For example, it is known to combine fixed-wing flight with the use of wheel-legs for ground movement. While such robotic vehicles are capable of efficient long-distance air travel, they typically require assisted take-off (e.g., an increased starting velocity provided by throwing or otherwise launching the vehicle, or provided by gravity-assisted take-off from a position that is elevated relative to the target, e.g., take-off from a roof or the like). As a result, the flight mode cannot always be activated at will to navigate over rough terrain and obstacles.
Fixed-wing aircraft may also have other drawbacks. For instance, due to the speed required to maintain lift, they may not always be suitable to operating indoors or in other semi-confined spaces.